Rear Axle fluid for G80 rear

Patrick · Post by **Patrick** » Wed Jan 01, 2003 5:35 pm

I am going to be changing my rear axle fluid soon. and am wondering if I could use Mobil 1 synthetic 75W90. 80W90 is in there now. Will this viscosity be all right?? Manual calls for 80W90.

Socaldave · Post by **Socaldave** » Wed Jan 01, 2003 7:27 pm

That weight gear oil will work fine. It is what I used and the drive train technician at the Chevy dealer recomended it as well. Do not use the additive.

Conman · Post by **Conman** » Wed Jan 01, 2003 9:19 pm

I just had my rear done and they put in the additive(well, I was charged atleast). I'm not sure what type of fluid they put in but I assume it's regular stuff, not Syn. I noticed the fullsize pickups have syn. from the factory now.

Cheers,

Con

a2b · Post by **a2b** » Wed Jan 01, 2003 10:27 pm

the additive has been debated tons of times. i dont have the g-80 so i dont care

Socaldave · Post by **Socaldave** » Thu Jan 02, 2003 9:13 am

Conman,

The regular GM Gear oil is a synthetic. As far as the additive being used I would not be concerned. I was told not to use it and I believe the owners manual says it is not recommended. I was also told that if changing the break-in fluid does not cure any noise issues or harsh engagement of the locker then to use the additive. The most important thing to remember is just to change the original break-in fluid. Just my 2 cents worth.